Modern communication and data networks comprise network nodes, such as routers, switches, bridges, and other devices that transport data through the network. Over the years, the telecommunication industry has made significant improvements to the network nodes to support an increasing number of protocols and specifications standardized by the Internet Engineering Task Force (IETF). Creating and coupling the complex network nodes to form networks that support and implement the various IETF standards (e.g., virtual private network (VPN) requirements) has caused modern networks to become complex and difficult to manage. As a result, vendors and third-party operators seek to customize, optimize, and improve the performance of the interwoven web of network nodes.
A software defined network (SDN) is a network technology that addresses customization and optimization concerns within convoluted networks. SDN architecture allows network administrators to have programmable central control of network traffic without requiring physical access to the network's devices. SDNs may be Internet Protocol (IP) networks utilizing Transmission Control Protocol/Internet Protocol (TCP/IP) protocols. SDNs may decouple the data-forwarding capability, e.g., the data plane, from routing, resource, and other management functionality, e.g., the control plane, previously performed in the network nodes. Decoupling the control plane from the data plane of the network enables the network controller to efficiently control the network traffic through globally optimized traffic engineering and routing, which departs from locally optimized shortest path first (SPF). SDN may also simplify network operations or even have the capabilities to flatten the network with extended data routing vectors.
The extended data routing vectors in SDN can cover network information from multiple Open Systems Interconnection (OSI) layers (e.g. Layer 2 (L2) and/or Layer 3 (L3)) for intelligent routing purposes. A basic approach to achieve decoupling of the network control from the network topology and data plane is by applying globally aware and topology decoupled software control at the edges of the network. The assumption is that traditional topology-coupled bridging and routing may be re-used at the core of the network so that scalability, interoperability, high availability, and extensibility of the conventional networking protocols, such as IP networks, can still be maintained. Network nodes that support SDN, e.g., SDN compliant nodes, may be configured to implement the data plane functions, while the control plane functions may be provided by an SDN controller. A group of nodes, e.g., routers, switches, etc., controlled by a single SDN controller may be referred to as an SDN domain.